There are many types of welding systems used for a variety of applications. Typical prior art welding systems include a power supply, such as phase control, inverter and converter based power supplies, and a controller that controls the output of the power supply. Welding systems reside at the core of the modern industrial age. From massive automated automobile assembly operations to manual, portable environments, these systems facilitate joining in ever more complicated manufacturing operations.
One such example of a welding system includes an electric arc welding system. Such a system may involve movement of a consumable electrode, for example, toward a work-piece while current is passed through the electrode and across an arc developed between the electrode and the work-piece. The electrode may be a non-consumable or consumable type, wherein portions of the electrode may be melted and deposited on the work-piece.
In certain arc welding applications, a supply of welding wire is typically pulled from a drum by a wire feeder and pushed through a welding cable and then through a welding gun which is movable along a work-piece. The welding gun typically includes a tubular contact tip allowing a welding current to be conducted to the wire moving through a wire receiving passage in the contact tip so the current between the wire and work-piece melts the wire for deposition of the metal onto the work-piece.
In electric arc welding technology, a power source passes a current between an electrode and a work-piece. Often, the electrode is a continuous welding wire drawn from a supply of welding wire, such as a drum or reel, and passed through a contact tip on its way to being melted and deposited onto the work-piece. In such a welding procedure, the power source of the welder includes a first stud connected to the electrode, usually through the contact tip, and a second stud connected to the work-piece. Connections are by welding cables, which cables may be quite long and include a variety of impedance variables, such as inductive reactance based upon length, position, and shape of the cables.
When performing a welding process, the power supply receives a current command to create a particular pulse wave between the electrode and work-piece. Such a welder must accurately control the pulse shape or waveform by controlling the voltage to a pulse width modulator operated at a frequency typically exceeding about 20 Khz. To assure the desired welding operation constituting specific waveforms between the electrode and work-piece, the command signal is created based upon a feedback from the actual welding operation. The feedback typically involves the arc current and/or arc voltage.
To control the welding process, welding power sources that provide waveform control have been developed. These power sources deliver a series of selectively shaped electrical power waveforms to the weld. The power waveform is optimized for a selected arc welding process, weld metal, wire feed speed, and weld joint.
Prior art controllers use a number of feedback parameters, including output current and output voltage. When output voltage is the feedback parameter, it is known in the prior art to feedback either power supply voltage or voltage from sense leads connected to the work-piece or bench, and the wire feed motor. Power supply voltage, as used herein, includes output voltage in or near the power supply, such as on the output studs. Voltage sense lead, as used herein, includes one or more leads used to sense output voltage remotely from the power supply, such as at the work-piece and/or the wire feeder.
The power supply voltage may differ from a sense lead voltage because of losses in the welding cable. Often, the power supply voltage is sufficient to control the power supply. Other times a more accurate voltage feedback is desired, and sense leads are used.
Sense leads typically connect to a specially designated sensor on the welding power supply. The negative voltage sense lead is typically clamped or clipped onto the work-piece or workbench, and the positive voltage sense lead is typically connected to the wire feed motor. The sense leads often lay on the ground between the welding power supply and the work-piece. Certain non-commercial prior art welding systems use a separate arc voltage sense wire that is clipped to a point near the welding electrode to more accurately measure arc voltage. Prior art commercial systems use a similar work-piece sense lead which is clipped to the work-piece.
Typically, to assure an accurate feedback of arc voltage, it is common practice to use remote voltage sensing leads directed from the controller of the power source to the electrode or contact tip and the work-piece. The voltage of these leads determines the command signal to the power source from the controller.
FIG. 1 is an exemplary illustration of a cross-sectional view of a coaxial welding cable assembly 100, in accordance with the prior art. Such a coaxial welding cable may be connected between a power source of a welding system and an electrode (or wirefeeder) and work-piece as described above.
The cable assembly 100 includes a central electrical conductor 110 having an outer, electrically insulating layer 115. Positioned around the insulated central conductor 110, 115 is a plurality of peripheral electrical conductors 120, each having an outer electrically insulating layer 125. The entire assembly is then wrapped in an electrically insulating jacket 130. Such a cable assembly, as constructed for welding applications, is typically heavy and stiff because of the multiple conductors and associated multiple layers of insulating material.
Therefore, there remains a need in the art for reducing the weight and increasing the flexibility of such coaxial welding cables.
Further limitations and disadvantages of conventional, traditional, and proposed approaches will become apparent to one of skill in the art, through comparison of such systems and methods with the present invention as set forth in the remainder of the present application with reference to the drawings.